Lumps somehow led us on (7)
I believe the answer is:
nodules
'lumps' is the definition.
(a nodule is a lump of cells in the body)
'somehow led us on' is the wordplay.
'somehow' is an anagram indicator.
'led'+'us'+'on'='leduson'
'leduson' with letters rearranged gives 'NODULES'.
(Other definitions for nodules that I've seen before include "Small swellings" , "Loudens like lumps" , "Loudens due to small lumps" , "Small rounded lumps" , "Small lumps - led us on (anag)" .)